ABSTRACT The goal of this U24 application is to establish a Coordinating Center (CC) for the next phase of the Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) sponsored by the NIH. The objective of ATN is to increase awareness among at-risk youth of their HIV status and, for those with HIV, achieve linkage, engagement and retention in the care continuum. Many challenges are faced by adolescents during their transition to young adulthood, resulting from developmental changes, peer influences, identity, and self-esteem formation. Risky behaviors among adolescents, which include engaging in unprotected sexual encounters or sharing nonsterile injecting drug paraphernalia, increase their likelihood of acquiring HIV infection. In the 2013 US Youth Risk Behavior Surveillance Survey (YRBSS), 34% of US high school students reported sexual intercourse during the prior 3 months, of which only 59% indicated condom use during last sexual intercourse. The YRBSS also found that only 13% of students had ever been tested for HIV infection. Given the global burden of new HIV infections among young people, greater involvement of adolescents in biomedical and behavioral HIV research is essential. However, significant individual, operational, and community-level barriers have been recognized to engaging adolescents in clinical prevention trials, which include insufficient understanding of research, need for parental consent, lack of access, mistrust and stigma associated with research participation. The new ATN is poised to address these issues. Central to its success will be an innovative, forward-looking, and productive Coordinating Center that brings cohesion to the participating U19 investigators by sharing their visions and providing scientific leadership, organizational support and analytic results for ATN projects. Key elements that will enhance collaboration and research progress include experienced leadership, innovative design and analysis methodologies, comprehensive research operations support, a state-of-the-art data management system, and superior administrative support. Our infrastructure will provide both public and private websites which include ATN information pages for the public, participants, and investigators, frequently asked questions, study materials, project calendar, a communications hub, and other features. We will develop a secure, user-friendly advanced data management system that includes web-based access for surveys, data entry, research management (including comprehensive reporting, biosample tracking and performance-based reimbursement tools), integration with external applications, and quality control. Our research operations and administration teams will provide a solid foundation to ATN by facilitating communication including meeting arrangements and minutes, collaborative document preparation, tracking of regulatory compliance, and support for abstract and publication preparation across the ATN. Together, this integrated structure will set the stage for collaboration and extraordinary research productivity from protocol development through research data sharing.